154 VERTEBRATES 



tine? What use has the bile? 



(2) Lay tlie fish on the right side and turn the liver 

 downward gently tearing away its threadlike attachments. 

 This uncovers a pinkish sac, the stomach. Pass a probe 

 back into the stomach through the mouth. Note its shape 

 and relation to the intestine. When the intestine comes 

 out of the front end of the stomach, it is said to be caecal. Is 

 the stomach of this fish caecal? Do you know of any ad- 

 vantage this may be ? 



Observe the intestine as it leaves the stomach. How 

 does it compare with the stomach in size? As you follow 

 it down does it get larger or smaller? 



(3) In many fishes, there are near this point of union 

 of stomach and intestine several wormlike branches matted 

 together. These are pyloric caeca. How many? How 

 arranged ? 



(4) Trace the intestine to its external opening, the 

 anus, and notice the thin membrane by which it is held in 

 place. That is the mesentery ; observe blood vessels in it. 

 Find a small, deep red body near the intestine, the spleen. 



Draw entire alimentary canal (Xi)- 



(5) In this intestinal cavity, you have probably already 

 seen the reproductive organs. These organs vary in size 

 with the season of the year and consist of one structure 

 in the female and two in the male. Examine these as to 

 size, color and composition. In the female search for a small 

 tube, the oviduct, leading from the larger mass, the ovary. 

 Where does it lead? In the male search for an opening 

 from each of the lobes, or spermaries which unite into a 

 tube or duct, the vas deferens as before. Find its place of 

 opening. 



